(Adapted from Applicant's Abstract): This research project is part of a larger, long-term effort to develop a minimally invasive and cost-effective method to ablate solid tumors using interventional MRI (iMRI) to guide and monitor therapy. A low-field, open magnet system is used to guide the tip of an ablation probe into the tumor and to monitor tissue destruction during the ablation procedure. Ablation occurs by heating from a radiofrequency (RF) energy source at the probe tip. Not only does MR provide tumor visualization, it can reveal the thermal lesion in various acquisition sequences (T2, STIR, etc.) and measure temperature changes. Potentially, these measurements can be used during clinical ablation procedures to determine tumor cell death and to minimize damage to normal surrounding tissue. The research addresses how well these MR measurements predict the actual tissue response. In this proposal, the applicants propose to address this issue using animal models. They will develop three-dimensional techniques to accurately register and correlate MR images with gross pathology and histology techniques. Ultimately, the goal will be to quantitatively predict cell damage and death using MR image acquisition and analysis methods, and a probabilistic state model that accounts for the cellular response to temperature history. With this research, the applicants expect to establish an analysis paradigm suitable for many future studies of contrast agents, ablation techniques, localized drug release, and other iMRI-guided therapies.